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LowpanCredential

public class LowpanCredential
extends Object

java.lang.Object
   ↳ com.google.android.things.lowpan.LowpanCredential


Describes a network access credential for a LoWPAN.

Currently, the only supported type of credential is that of a "master key", which is a fixed-length symmetric shared secret. The valid length for the master key is defined by the underlying LoWPAN type, but is typically fixed to a length of 16 bytes (128 bits).

The master key is shared by all devices participating in the LoWPAN and is used by the underlying network technology to derive other secrets for the purposes of device access control and data encryption/authentication.

There is typically no need to randomly generate a master key yourself: A master key is automatically generated when a LoWPAN is formed using a LowpanProvisioningParams with an unspecified LowpanCredential via form(LowpanProvisioningParams).

Note that a master key is always a sequence of random or pseudorandom bytes. Thile value of the master key can be derived from a passphrase using a network-type-defined key-streching algorithm, a master key is never the raw bytes of a password or passphrase.

Summary

Public methods

static LowpanCredential createMasterKey(String masterKeyHex)

Constructs a LowpanCredential with the given master key encoded as a hexidecimal string.

static LowpanCredential createMasterKey(byte[] masterKey)

Constructs a LowpanCredential with the given master key.

boolean equals(Object rhs)

Indicates whether some other object is "equal to" this one.

byte[] getMasterKey()

Returns the bytes of the master key if this LowpanCredential contains a master key.

int hashCode()

Returns a hash code value for the object.

boolean isMasterKey()

Returns true if this LowpanCredential is a symmetric master key, false otherwise.

String toString()

Returns a string representation of the object.

Inherited methods

From class java.lang.Object

Public methods

createMasterKey

LowpanCredential createMasterKey (String masterKeyHex)

Constructs a LowpanCredential with the given master key encoded as a hexidecimal string.

Parameters
masterKeyHex String

Returns
LowpanCredential

createMasterKey

LowpanCredential createMasterKey (byte[] masterKey)

Constructs a LowpanCredential with the given master key.

Parameters
masterKey byte

Returns
LowpanCredential

equals

boolean equals (Object rhs)

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Parameters
rhs Object: the reference object with which to compare.

Returns
boolean true if this object is the same as the obj argument; false otherwise.

getMasterKey

byte[] getMasterKey ()

Returns the bytes of the master key if this LowpanCredential contains a master key.

Returns
byte[]

hashCode

int hashCode ()

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java™ programming language.)

Returns
int a hash code value for this object.

isMasterKey

boolean isMasterKey ()

Returns true if this LowpanCredential is a symmetric master key, false otherwise.

Returns
boolean

toString

String toString ()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Returns
String a string representation of the object.